The present invention relates to a steering wheel for motor vehicles which has deformable flat steel spokes connecting a steering-wheel rim to a hub to be mounted on a steering shaft, and, more particularly, to a steering wheel in which the associated free ends of the spokes are cast into the cast hub, and each spoke has in the cast-in area a passage bore extending in the axial direction of the steering wheel and being penetrated by the hub material during the casting process.
Mercedes-Benz AG has produced vehicle steering wheels in which the passage bore is located in an area of the hub near to the steering shaft and serves as protection against the spoke/hub connection being loosened in the radial direction.
The present invention recognizes that, in the event of a head-on collision, the known steering wheel is loaded by the driver and deformed forwards while absorbing energy in the driving direction. In this situation, it is important that the spokes, on leaving the hub, are held in their position and deform in a defined manner in a foreseen rolling area in a large radius. On leaving the hub, however, the spokes buckle too quickly, for example, due to the breaking up of the cast-around material, the hub material consisting preferably of aluminum, and the steering column located below it then prevents and impedes the advance path of the spokes. The force can then rise, under certain circumstances, to undesired values.
A relatively large dimensioning might provide a possible remedy, but such a remedy cannot always be realized due to the narrow space available in the steering wheel/steering-column jacket area.
The present invention has an object of overcoming the aforementioned disadvantages and ensuring sufficient rigidity in the area in question without increasing the external dimensions of the components involved.
This object has been achieved according to the present invention in a steering wheel by arranging the passage bore directly adjacent to the entry area of the spoke into the hub to form a rolling step, such that in this entry area a tension-rod connection is formed between the hub material located above and below the spoke.